module Checker

rascal-0.28.2

typepal-0.8.3

Usage

import examples::structParameters::Checker;

data AType

data AType  
     = intType()
     | strType()
     | typeFormal(str name)
     | structDef(str name, list[str] formals)
     | structType(str name, list[AType] actuals)
     ;

data IdRole

data IdRole  
     = fieldId()
     | structId()
     | typeFormalId()
     ;

function prettyAType

str prettyAType(intType()) = "int";

str prettyAType(strType()) = "str";

str prettyAType(typeFormal(name)) = "<name>";

str prettyAType(structDef(name, formals)) = isEmpty(formals) ? "<name>" : "<name>[<intercalate(",", formals)>]";

str prettyAType(structType(name, actuals)) = isEmpty(actuals) ? "<name>" : "<name>[<intercalate(",", [prettyAType(a) | a <- actuals])>]";

function structParametersInstantiateTypeParameters

AType structParametersInstantiateTypeParameters(Tree current, structDef(str name1, list[str] formals), structType(str name2, list[AType] actuals), AType t, Solver s){

    if(size(formals) != size(actuals)) throw checkFailed([]);

    bindings = (formals[i] : actuals [i] | int i <- index(formals));

    

    return visit(t) { case typeFormal(str x) => bindings[x] };

}

default AType structParametersInstantiateTypeParameters(Tree current, AType def, AType ins, AType act, Solver s) {

    return act;

}

function structParametersGetTypeNamesAndRole

tuple[list[str] typeNames, set[IdRole] idRoles] structParametersGetTypeNamesAndRole(structType(str name, list[AType] actuals)){

    return <[name], {structId()}>;

}

default tuple[list[str] typeNames, set[IdRole] idRoles] structParametersGetTypeNamesAndRole(AType t){

    return <[], {}>;

}

function structParametersGetTypeInNamelessType

AType structParametersGetTypeInNamelessType(AType containerType, Tree selector, loc _, Solver s){

    s.report(error(selector, "Undefined field %q on %t", "<selector>", containerType));

    return intType();

}

function structParametersConfig

TypePalConfig structParametersConfig() =

    tconfig(getTypeNamesAndRole = structParametersGetTypeNamesAndRole,

            getTypeInNamelessType = structParametersGetTypeInNamelessType,

            instantiateTypeParameters = structParametersInstantiateTypeParameters);

function collect

void collect(current:(Declaration)`<Type typ> <Id id> = <Expression exp> ;`, Collector c) {

    c.define("<id>", variableId(), current, defType(typ));

    c.requireEqual(typ, exp, error(exp, "Incorrect initialization, expected %t, found %t", typ, exp));

    

    c.enterScope(current);

        collect(typ, exp, c);

    c.leaveScope(current);

}

void collect(current:(Declaration) `struct <Id name> <TypeFormals formals> { <{Field ","}* fields> };`, Collector c) {

    type_formal_list = formals is noTypeFormals ? [] : [f | f <- formals.formals];

    c.define("<name>", structId(), current,  defType(structDef("<name>", [ "<tf>" | tf <- type_formal_list])));

    c.enterScope(current);

        for(tf <- type_formal_list){

            c.define("<tf>", typeFormalId(), tf, defType(typeFormal("<tf>")));

        }

        collect(formals, fields, c);

    c.leaveScope(current);

}

void collect(current:(Field)`<Type typ> <Id name>`, Collector c) {

    c.define("<name>", fieldId(), current, defType(typ));

    collect(typ, c);

}

void collect(current:(Type)`int`, Collector c) {

    c.fact(current, intType());

}

void collect(current:(Type)`str`, Collector c) {

    c.fact(current, strType());

}

void collect(current:(TypeFormals) `[ <{TypeFormal ","}+ formals> ]`, Collector c){

    collect(formals, c);

}

void collect(current:(TypeActuals) `[ <{Type ","}+ actuals> ]`, Collector c){

    collect(actuals, c);

}

void collect(current: (Type) `<Id name> <TypeActuals actuals>`, Collector c){

    c.use(name, {structId(), typeFormalId()});

    if(actuals is withTypeActuals){

        tpActuals = [tp | tp <- actuals.actuals];

        c.calculate("actual type", current, name + tpActuals,

            AType(Solver s) { 

                return structType("<name>", [s.getType(tp) | tp <- tpActuals]);});

            

        collect(actuals, c);

    } else {

        c.fact(current, name);

    }

}

void collect(current:(Expression) `new <Id name><TypeActuals actuals>`, Collector c){

    c.use(name, {structId()});

    actual_list = actuals is noActuals ? [] : [a | a <- actuals.actuals];

    c.calculate("new `<name>`", current, name + actual_list,

        AType(Solver s){

            if(structDef(_, formals) := s.getType(name)){

                formal_list = [f | f <- formals];

                if(size(actual_list) != size(formal_list)){

                    s.report(error(actuals, "Expected %v type parameters, but got %v", size(formal_list), size(actual_list)));

                }

            } else {

                s.report(error(name, "Illegal type in `new`, expected `struct` found %t", name));

            }

            return structType("<name>", [s.getType(a) | a <- actual_list]);

        });

    collect(actuals, c);

}

void collect(current:(Expression)`<Expression lhs> . <Id fieldName>`, Collector c) {

    c.useViaType(lhs, fieldName, {fieldId()});

    c.calculate("FIELD SELECT", current, [lhs, fieldName],          // Hackish solution, error in Solver?

        AType(Solver s) { 

            tp = s.getType(fieldName); 

            if(typeFormal(str _) := tp) throw TypeUnavailable();

            return tp;

            

            });

    //c.fact(current, fieldName);                                   // <-- this should be enough

    collect(lhs, c);

}

void collect(current:(Expression)`<Integer _>`, Collector c) {

    c.fact(current, intType());

}

void collect(current:(Expression)`<String _>`, Collector c) {

    c.fact(current, strType());

}

void collect(current:(Expression)`<Id use>`, Collector c) {

    c.use(use, {variableId()});

}